On Thursday, Prime Minister Anibal Torres traveled to the Andean region of Apurimac, but he arrived late and then abruptly left the meeting only an hour after it had started.
Researchers are analyzing individual hair samples from people living and working around the Witwatersrand basin to determine the degree of uranium contamination.
Last year, environmentalists and surrounding communities appealed a ruling from a lower court that tossed out a decision by a regulator that denied the company permits.